Pilfer `__init__` methods for simulation operations

[mphoward]

To reduce maintenance, we should borrow the __init__ methods for the delegating simulation operations in the implementations like:

class EnsembleAverage:
    __init__ = analyze.EnsembleAverage.__init__

since 99% of the time, these do exactly the same thing.

[mphoward]

This will cause more headaches than it is worth worrying about inheritance, closing.